Guillain-Barré Syndrome Warning Added to Shingrix Vaccine in Australia

In February 2024, Australia’s Therapeutic Goods Administration (TGA), the country’s national regulatory authority for drugs and, initiated an investigation into a potential association between GSK plc’s Shingrix shingles vaccine, Guillain-Barré syndrome (GBS), which causes inflammation and damage to the nerves, that may include paralysis.¹

The investigation was prompted by two reports of GBS following Shingrix vaccination. Around the same time, similar cases had been recorded in the World Health Organization’s (WHO) global adverse event database. Published literature also suggested a possible link between Shingrix and GBS, further supporting the need for an investigation.²

As of Sept. 18, 2024, Australia’s public Database of Adverse Event Notifications recorded 13 cases of GBS following Shingrix vaccination. The cases involved individuals aged between their mid-60s and mid-80s, and included both males and females. No fatalities were reported.³

Update to Australian Shingrix Vaccine Product Information

Although GBS was already listed in the Product Information for Shingrix in the United States and Canada, it had not yet been included in the Australian Product Information. Following the investigation, a recommendation was made to add GBS to the adverse events section of the Australian Product Information for Shingrix on Oct. 24, 2024. This update ensures alignment with the regulatory information provided in the United States and Canada.⁴

Shingrix is a recombinant subunit adjuvanted vaccine that contains a non-live component of the varicella-zoster virus, which causes chickenpox and shingles (herpes zoster). Shingrix vaccine was approved by the U.S. Food and Drug Administration (FDA) on Oct. 20, 2017, for use in adults aged 50 years and older, as well as in adults aged 18 years and older who are or will be at increased risk of herpes zoster (HZ) due to immunodeficiency or immunosuppression caused by known diseases or therapies.⁵ In Australia, Shingrix was approved for use in June 2021.⁶

GBS is a neurological condition in which the immune system affects the peripheral nerves. While the exact cause is not fully understood, it can sometimes develop after infections such as influenza, and has also been reported following certain vaccinations, including influenza and COVID-19 shots. The condition leads to nerve inflammation and can cause symptoms such as pain, numbness, muscle weakness, difficulty walking or breathing and in some cases, quadriplegia that paralyzes all four limbs.⁷  Many individuals recover, although recovery can take months or years, and some may continue to experience residual weakness.⁸

Review by Australian Independent Expert Advisory Group

An Australian independent expert advisory group on vaccination reviewed the potential association between GBS and Shingrix. The review included a report of a single adverse event involving meningoencephalitis, though the primary focus remained on GBS. The expert group concluded that it was appropriate to include GBS as an adverse event in the Australian Shingrix Product Information and recommended raising awareness about the potential for GBS following vaccination.⁹

U.S. Post-Marketing Review Identifies Potential Shingrix/GBS Link

In a 2021 post-marketing safety review, the U.S. Centers for Disease Control and Prevention (CDC), the FDA, and the Centers for Medicare & Medicaid Services (CMS) evaluated whether there was a link between Shingrix and GBS in adults aged 65 and older.

Based on data from more than 3.7 million administered doses, the analysis found a small increased risk of GBS, particularly within 42 days after the first dose, estimated at approximately three to six additional cases per million doses. No increased risk was observed after the second dose. The FDA recommended updating the Warnings and Precautions section of the Shingrix prescribing information  to include this potential risk.¹⁰a>

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